FORTUNE — Godfrey Sullivan has an odd idea of fun. For the past two decades the 59-year-old chairman and CEO of data analytics firm Splunk has competed in a little-known type of race called Ride and Tie: Two partners alternate between riding a horse and running on long, rugged courses. “After you’ve run 30 or 40 miles in the mountains, your dependency on your team is crystal clear,” he says. It’s not unlike managing his company.
San Francisco-based Splunk (SPLK) sells software aimed at IT departments that want to make sense of machine data — the mountains of files created by servers, apps, and devices “talking” to one another. Customers include the U.S. Defense Department, Facebook (FB), and Staples (SPLS). Splunk — the name comes from “spelunking,” the sport of exploring wild caverns — went public in April 2012. The stock generated one of the biggest first-day gains of 2012, doubling at its opening. (Overall, the stock is up about 84%.) The company says revenue for the current fiscal year is on track to be $194 million, up 62% from the year before. The 650-person company hasn’t turned a profit, but analysts are enamored of its potential.
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Despite his hard-core extracurriculars — he’s also an avid fan of endurance horse riding — Sullivan has earned a reputation as one of Silicon Valley’s most level-headed CEOs. Case in point: Sullivan didn’t bring in an entourage, change Splunk’s corporate culture, or push out its founders when he was brought in four years ago to take the company public.
Michael Baum, Splunk’s founding CEO and now a partner at Rembrandt Venture Partners, says Sullivan acted “selflessly” as he transitioned into the CEO role and Baum prepared to leave. “You don’t blow the place up,” Sullivan explains. “You learn and you accept.”
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Sullivan grew up middle class in Waco, Texas. He describes himself as a latchkey kid with pyromaniac tendencies. (He once lit a fire in his bedroom.) After graduating from Baylor University, he moved west and eventually landed at Apple (AAPL) as a sales director. “Godfrey proves you don’t have to backstab everybody to get ahead,” says Carol Bartz, who hired Sullivan in 1992 when she was CEO of Autodesk (ADSK).
Not surprisingly, Sullivan likens his company’s trajectory to a race: The IPO was just “mile three” of a marathon. Now Splunk must live up to the hype — not to mention a $3 billion market cap. It also has to contend with competitors like Oracle (ORCL) and IBM (IBM). Luckily, Sullivan is plenty comfortable with long and grueling runs.
This story is from the February 4, 2013 issue of Fortune.